In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water. The absorption spectrum for varying concentrations of Fe2+ are measured using a spectrophotometer and the data is graphed in Excel. The slope of the line is ε in the Beer-Lambart equation A = εcl. In the second part of the experiment, eleven flasks containing diluted stock solutions of Fe2+ and ligand are mixed with 5 mL 2 M sodium acetate and 4 mL 3 M NH2OH and diluted with water. The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel.
(Divide the mass of the liquid calculated above by the volume of the liquid.) Trial 1: 10.5 / 8.7 = 1.21 Trial 2: 11 / 8.5 = 1.29 Trial 3: 11.4 / 8.8 = 1.30 Part II: Density of Irregular-Shaped Solid Calculate the volume of the irregular-shaped solid for each trial. (Subtract the volume of the water from the total volume of the water and solid.) Trial 1: 50.7 - 50.2 = .5 Trial 2: 50.7 - 50.2 = .5 Trial 3: 50.5 - 50.1 = .4 Calculate the density of the irregular-shaped solid for each trial. (Divide the mass of the solid by the volume of the solid calculated above.)
Analysis of a Commercial Bleach Lab Guidelines • Name, Exp. Name, Number, Date (we did lab), Partner(s) • Purpose • Compound Names, Formulas, and Molar Masses (5 used – no formula or molar mass for starch) • Reactions (use the four listed on the front page of the lab) • Procedure/Observations • Include initial observations and final observations/odors, masses of KI… • Results (Data Table) • Make a table that has your data of KI masses, and the three volumes (from the three trials) needed to titrate the bleach • Calculations (Data and Calculations Section in lab) 1. Use the equations given on the front page to determine the number of moles of sodium thiosulfate that are equivalent to one mole of sodium hypochlorite. 2. From your three trials, calculate the average volume of Na2S2O3 needed for the titration of 25.00mL of diluted bleach.
Experiment 5: Titration for Acetic Acid in Vinegar Name: Lab Partners: None Date of Experiment: March 25th, 2013 Location: My House Course Number: Chem 112 Abstract: In this experiment the objectives were develop familiarity with the concepts and techniques of titration and to determine the concentration of an acetic acid solution in vinegar. Experiment and Observation: Data Table 1: Quantity of NaOH needed to Neutralize 5 mL of Acetic AcidBrand of Vinegar Used: Heinz White Distilled VinegarLabel Notes: ______________________ | | Initial NaOH reading(Interpolate to 0.1 mL) | Final NaOH reading(Interpolate to 0.1 mL) | Volume of NaOH used | Trial 1 | 9.5 | 1.3 | 8.2 | Trial 2 | 9.7 | 1.4 | 8.3 | Trial 3 | 9.6 | 1.4 | 8.2 | Average volume of NaOH used: | 8.2 | Calculations and Errors: Errors: Calculations: A. Calculate the average number of mL of NaOH used for the 3 trials and record. B. Calculate the Normality of the vinegar using the previously given equation.
LAB 6 ANALYSIS OF WATER IN PHOSPHATE Name: Lab Partners: None Date of Experiment: November 13, 12 Location: My House Course Number: CHE111C21 Abstract: In this experiment, we used a simple colorimeter and Beer’s Law to find the concentration of a tap water sample. A Beer’s law calibration curved was drawn showing the absorbance of varying concentrations of phosphate. Phosphate solutions will produce standard colors when mixed with ammonium molybdate and stannous chloride. The concentration of the unknown solution containing phosphate will be determined using the calibration curve. A voltmeter was used to measure the electrical resistance of different solutions.
Part C: Density of Sodium Chloride (NaCl) Solution, a sample of NaCl was obtained and measured using a 100mL beaker and a 10mL pipet to determine the concentration of the solution. In order to obtain the appropriate result, a calibration graph and density measurement was used to determine the concentration of the sodium chloride solution. In conclusion, based on the water temperature of 21.8°C in part A’s graduated cylinder experiment obtained, it was determined that the average density was .0973g/mL with a percentage error of 2.5%. When graphed the measurement was equal to Y=0.988x. Part B: The graduated pipet’s average density at 22.3 °C was determined to be 0.9785g/mL with a percentage error of 1.89% shows the graduated pipet to be more accurate and precise.
The first test tube will be control, the second will be substrate and indicator dye, the third will be dilute extract, the fourth will be the same contents as the second, the fifth will be medium concentration of extract, the sixth will be the same contents as the second, and the seventh will be concentrated extract. 3) Add stock solutions to each tube using the corresponding graduated 5 ml pipette or dispensing device. 4) Adjust the spectrometer to zero absorbance at 500nm. Pour contents of test tube 1 into a cuvette. ) Make sure to keep time, read the spectrometer, and record the data.
The solution was then drained into an Erlenmeyer flask and I recorded the weight of the flask before (W1) and after the solution (W2) and then subtract the weight of the flask with the solution from the weight of the flask alone in order to find the absolute mass of the solution (W3). I repeated these steps 2 times. In order to find the density (D) of the solution I took the mass of the solution (∆W) and divided it by volume of the solution in the buret. I then averaged the two densities and found that the average density for the egg to float is 1.05g/mL. | 1st | 2nd | | Buret volume: 24mL | Buret volume: 24.1mL | W2 | 141.87g | 141.83g | W1 | 115.18g | 116.15g | ∆W = W2 – W1 | 25.06g | 25.37g | D = ∆W/buret volume | 1.04g/mL | 1.06g/mL | Average Density = 1.04 + 1.06 / 2 = 1.05 | I repeated the same process for the Mohr pipet as I did for the Buret.
The known nutrient solutions were used to create a base-line for protein, starch, and sugars. As listed in Table 1; protein (5g/L), Starch (0.2g/L), and sugar (20g/L) were separated in to 9 different test tubes at 2ml a piece, 3 per nutrient solution and tested for colormetry with the 400ug of the three reagents Lugol’s, Biuret, and Benedicts. Further steps were taken with the nutrients treated with Benedict’s reagent and they were heated in a water bath until they reached a constant 65 degrees C for 7 minutes and let cool to see color change. Distinguishing Organic Molecules in Unknown Dietary Supplements The same reagents used in setting the baseline were used to test the unknowns for nutrient content. Each of the 3 unknowns was distributed by dispensing 2ml of sample solution in to three test tubes.
The resulting product was [Co(NH3)5Cl]Cl2 and yield was 4.453g (.017 mol, 84.8%) Distilled water (25mL) was added to concentrated ammonia (5mL) in a 125mL Erlenmeyer flask. The reaction was heated and stirred, then [Co(NH3)5Cl]Cl2 (.0060 mol) was added to the solution. The reaction mixture was vacuum filtered, and the filtrate was cooled in an ice bath. 6M HCl was then added until the solution was neutral to litmus. NaNO2 (.0217 mol) was added to the solution and was allowed to react for five minutes.